This invention relates generally to automatic tracking systems for use with automatic music playing machines. Specifically this invention relates to a pneumatic system for automatically centering the music roll of perforated paper and maintaining it in alignment with sensors located on the customary tracker bar. Prior methods of maintaining this alignment were bulky and complex requiring multiple sensing devices. This necessitated multiple pressure actuated pneumatic devices and linkage connected to each of the alignment sensors. A change in pressure or air flow over the alignment sensor caused the corresponding pheumatic drive to operate mechanical linkage arranged to position the feed roller. The drawbacks to these systems were generally their size and complexity.